Method for the quantitative determination of soldering agent residues

Abstract

A method for quantitatively determining flux material residues remaining on a heat exchanger after a preceding soldering process is provided. To this end, a fluid is applied to the heat exchanger, wherein the remaining quantity of flux material on the heat exchanger after the preceding soldering process is derived from the concentration of soldering agent in the fluid.

Description

[0001]This nonprovisional application is a continuation of International Application No. PCT / EP2010 / 068096, which was filed on Nov. 24, 2010, and which claims priority to German Patent Application No. DE 10 2009 055 610.9, which was filed in Germany on Nov. 25, 2009, and which are both herein incorporated by reference.BACKGROUND OF THE INVENTION[0002]1. Field of the Invention[0003]The invention relates to a method for the quantitative determination of soldering aid residues, which remain on a workpiece after a preceding processing step, in which the workpiece is acted upon by a fluid. Further, the invention relates to an apparatus which is suitable to a particular degree for carrying out the method. Moreover, the invention relates to a method for dimensioning a workpiece and / or another part.[0004]2. Description of the Background Art[0005]During the processing of workpieces, it is typical in certain processing steps and often also necessary that they be treated with an auxiliary mate...

AI Technical Summary

Benefits of technology

[0012]It is especially advantageous when the proposed method is carried out in such a way that a defined volume of fluid is used. As a result, it is possible especially simply, for example, to derive the soldering aid amount remaining on and / or in the workpiece from the soldering aid concentration in the fluid. It is possible as a result, moreover, to adapt the “testing environment” especially well to the later actual installation situation. When the workpiece, for example, is a coolant cooler for a motor vehicle, thus the measuring method can be carried out particularly with a fluid volume that corresponds to the coolant volume in the vehicle coolant circuit. Naturally, it is likewise possible to carry out the method also with varying fluid volumes, to determine the fluid volume, and to convert the obtained values appropriately.

[0015]It is especially advantageous, further, when the workpiece is made at least in sections of aluminum, of an aluminum alloy, of nonferrous metal, and / or of a nonferrous metal alloy. Such materials in particular often require soldering aids for their processing, especially for their soldering and / or welding, so that they can be processed reasonably or at all.

[0020]It is proposed, further, to carry out the method in such a way that at least at times and / or at least partially it is carried out as a circulation process. In particular, this can be a closed circulation process. It is possible in this way to determine the remaining soldering aid amount especially well, particularly largely completely, without an excessive amount of fluid being necessary. Moreover, the measuring accuracy of the method can improve, because a relatively high concentration value in the fluid is ultimately measured, which typically results in lower measuring accuracies. Moreover, the consumption of fluid can be reduced and, for example, the energy necessary for carrying out the method (particularly heat energy for the fluid) can be reduced, which is also an advantage.

[0022]It has also proven advantageous, when at least one cleaning process is carried out in the method before and / or after a measurement. In this way, the system can be cleaned, so that, for example, soldering aid residues from prior measurements can be removed reliably, and thus have no effect or only a marginal effect on subsequent measurements. This also can prove to be essential for the reliability of the determined measured values.

[0024]It is proposed to design the apparatus preferably in such a way that it has at least one equalizing tank, at least one electronic control device, at least one temperature control device, at least one sensor device, at least one preferably controllable fluid supply option, at least one preferably controllable fluid removal option, and / or at least one bypass device. With the use of the electronic control device it is especially possible to achieve automated, reproducible, and / or especially meaningful measured values which are especially simple to determine. Using a temperature control device (heating and / or cooling) it is especially possible to adjust the fluid to a suitable temperature. Different values can be determined by using at least one sensor device, especially the actual measured values, but optionally also “auxiliary values” such as the fluid temperature or the like. With the use of the fluid supply option or the fluid removal option, it is possible to take samples, to add additives, to replace or replenish the fluid, and / or the like. Preferably, in this case, the fluid supply option and / or the fluid removal option can be controlled externally, such as particularly with the use of the electronic control device. With the use of the equalizing tank, it is possible in particular to leave, for example, a closed circuit sufficiently filled, also when samples are taken or liquid and / or additives are added (repeatedly if necessary). A bypass device is advantageous particularly because the fluid can be conditioned beforehand (for example by heating or cooling, whereby the fluid can be conditioned especially homogeneously), without the fluid first flowing through the workpiece to be tested (test piece). It is particularly possible in this way to begin the actual measurement under especially well reproducible starting conditions (closing of the bypass and opening of the actual circuit), as a result of which especially informative measured values can be obtained.

Problems solved by technology

Typically, the use of flux materials also entails flux material residues on the workpiece and thereby the associated disadvantages.

In particular, after the workpiece is finished, soldering agent residues remaining on it can impair the function and durability of other components, working together with the soldered workpiece, and possibly also the workpiece itself, for example, by corrosion.

In fact, it is basically possible to remove soldering agent residues from the workpiece after the soldering process has been completed (for example, by washing), but this can prove to be costly and complicated, particularly when the subsequently necessitated drying processes for the workpiece are considered in addition.

Reduction of the amount of the used flux material is also not easily possible, because such a decrease in the flux material amount can entail a worsening of the soldering result, which is likewise undesirable.

The aforementioned problems arise especially to a particular degree when it concerns the processing of workpieces that have especially fine structures and / or especially many curved surfaces (particularly also with small radii of curvature) and in part closed hollow spaces.

Because of the varied hollows spaces in such heat exchangers, washing of the heat exchanger after soldering proves to be tedious and problematic.

A reduction in the amount of employed flux material is also out of the question, because due to the large proportion of parts to be soldered together the risk of leaking would rise very rapidly to no longer acceptable values.

Another problem occurring in practice is that with the use of soldering aids, particularly of flux materials, empirical values are often drawn upon, when it is a matter of determining the amount of soldering aids to be used during the processing of the workpiece.

Because resoldering of workpieces is relatively complicated and expensive, the tendency therefore is to select the amount of the employed soldering aid as higher than the actually necessary amount (this also applies to scrap workpieces).

This leads not only to an unnecessarily high consumption of soldering aids (which entails corresponding production costs and environmental pollution unnecessary per se), but also to the situation that the workpiece and other parts, operated together with the workpiece, in a machine are exposed to correspondingly higher wear by the (unnecessarily) high soldering aid residues, and accordingly must be constructed as more durable.

This also leads to disadvantages such as particularly cost and weight disadvantages.

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